1. Field of the Invention
The present invention relates generally to printing presses and more particularly to a device and method for driving rolls and cylinders in a printing press.
2. Background Information
Offset lithographic printing presses typically have a plate cylinder carrying an imaged plate. During printing, the plate is inked, and the inked image is transferred to a blanket which then contacts paper sheets or a continuous web of paper. Ink for the plate cylinder may be provided via an anilox inker, which has an anilox roller having a series of cells for providing ink via a roller to a plate cylinder.
The drive for an offset lithographic printing press traditionally has included a common drive shaft running on a gear side of the printing press, with worm gears and other gears deriving power from the shaft.
Other shaftless drive configurations for lithographic offset printing presses use direct or indirect drive motors, which supply the necessary driving forces to the plate and/or blanket cylinders using one to four motors. A separate or additional motor typically is used to drive the ink fountain.
Commonly-owned U.S. Pat. No. 6,050,185, issued Apr. 18, 2000, purports to disclose a shaftless drive with a first drive motor driving a first inker roller either directly or via a further drive. The first drive motor is mechanically coupled to the first plate cylinder via a first gear train, which may include a gear wheel mounted to the drive shaft of the first plate cylinder. A second drive motor drives another plate cylinder and inker roller. The first blanket cylinder and the second blanket cylinder of the press are mechanically coupled to one another and are driven by a third drive motor.
The '185 patent does not disclose an anilox inker, nor does it disclose a two-motor configuration, an inking form roll or an inking roll with a similar diameter to the plate cylinder.
European Patent Application No. 0 699 524 purports to disclose an offset printing machine. Cylinder and functional groups are driven with minimum technical requirements. A printing unit is provided where the plate cylinders are each driven by a separate electric motor and are not mechanically coupled to each other. Independently driven cylinders in a folder are also disclosed.
International Patent Application No. 95/24314 and related U.S. Pat. No. 5,782,182 purport to disclose a printing group for a color-printing web-fed rotary press arranged in a bridge design. The bridge units may be symmetrically distributed in the vertical direction and horizontally movable, to achieve a low height. Each unit side has a plate cylinder and a blanket cylinder. An inking unit for the plate cylinder may include, in place of an inking trough and an inking roller, a chamber doctor blade in connection with an anilox roll. The drive of the dampening unit and of the inking unit can function through friction with the plate cylinder, or by means of an individual motor drive of the inking roller and of the dampening agent application roller, or by means of know gear wheel drives. No driving of the plate cylinder through a motor directly driving the inking unit is disclosed. Moreover, when a drive motor is directly connected to the plate cylinder, proper lateral registration is complicated.